package com.example.websocket.server;

import com.example.websocket.utils.JacksonUtils;
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.lang3.StringUtils;
import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.Optional;
import java.util.concurrent.ConcurrentHashMap;

@Slf4j
@ServerEndpoint("/websocket/{userId}")
@Component
public class WebSocketServer {

    /**
     * 静态变量，用来记录当前在线连接数。应该把它设计成线程安全的
     */
    private static volatile int onlineCount = 0;
    /**
     * concurrent包的线程安全Map，用来存放每个客户端对应的MyWebSocket对象。
     */
    private static ConcurrentHashMap<String, WebSocketServer> webSocketMap = new ConcurrentHashMap<>();
    /**
     * 与某个客户端的连接会话，需要通过它来给客户端发送数据
     */
    private Session session;
    /**
     * 接收userId*
     */
    private String userId = "";


    /**
     * 连接建立成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session, @PathParam("userId") String userId) {
        this.session = session;
        this.userId = userId;
        if (webSocketMap.containsKey(userId)) {
            webSocketMap.remove(userId);
            //加入Map中
            webSocketMap.put(userId, this);
        } else {
            //加入Map中
            webSocketMap.put(userId, this);
            //在线数加1
            addOnlineCount();
        }
        log.info(">>>用户连接userId:" + userId + ",当前在线人数为:" + getOnlineCount());
        try {
            sendMessage(">>>连接成功");
        } catch (IOException e) {
            log.error(">>>用户userId:" + userId + ",网络异常!!!!!!");
        }
    }

    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        if (webSocketMap.containsKey(userId)) {
            //从Map中删除
            webSocketMap.remove(userId);
            subOnlineCount();
        }
        log.info(">>>用户退出,userId:" + userId + ",当前在线人数为:" + getOnlineCount());
    }

    /**
     * 收到客户端消息后调用的方法
     *
     * @param message 客户端发送过来的消息
     */
    @OnMessage
    public void onMessage(String message, Session session) {
        log.info(">>>发送消息,userId:" + userId + ",报文:" + message);
        //可以群发消息
        if (StringUtils.isNotBlank(message)) {
            try {
                //解析发送的报文
                Optional<Map<String, Object>> optionalMap = JacksonUtils.str2Map(message, String.class, Object.class);
                Map<String, Object> map = optionalMap.isPresent() ? optionalMap.get() : new HashMap<>();
                //追加发送人(防止串改)
                map.put("fromUserId", this.userId);
                String toUserId = "";
                if (map.containsKey("toUserId")) {
                    toUserId = map.get("toUserId").toString();
                }
                if (StringUtils.isNotBlank(this.userId) && StringUtils.isNotBlank(toUserId)) {
                    if (this.userId.equals(toUserId)) {
                        //不能给自己发送消息
                        log.warn(">>>不能给自己发送消息,fromUserId:{},toUserId:{}", this.userId, toUserId);
                    } else {
                        //传送给对应toUserId用户的websocket
                        if (StringUtils.isNotBlank(toUserId) && webSocketMap.containsKey(toUserId)) {
                            Optional<String> optionalStr = JacksonUtils.obj2Str(map);
                            String msg = optionalStr.isPresent() ? optionalStr.get() : "";
                            webSocketMap.get(toUserId).sendMessage(msg);
                        } else {
                            log.error(">>>请求的userId:" + toUserId + "不在该服务器上");
                            // todo 否则不在这个服务器上，发送到mysql或者redis
                        }
                    }
                }
            } catch (Exception e) {
                log.error(">>>发送消息异常", e);
            }
        }
    }

    /**
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        log.error(">>>发生错误:" + this.userId + ",原因:" + error.getMessage());
    }

    /**
     * 实现服务器主动推送
     */
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }


    /**
     * 发送自定义消息
     */
    public static void sendInfo(String message, @PathParam("userId") String userId) throws IOException {
        log.info(">>>发送消息到userId:" + userId + "，报文:" + message);
        if (StringUtils.isNotBlank(userId) && webSocketMap.containsKey(userId)) {
            webSocketMap.get(userId).sendMessage(message);
        } else {
            log.error(">>>用户userId[" + userId + "],不在线！");
        }
    }


    public static synchronized int getOnlineCount() {
        return onlineCount;
    }

    public static synchronized void addOnlineCount() {
        WebSocketServer.onlineCount++;
    }

    public static synchronized void subOnlineCount() {
        WebSocketServer.onlineCount--;
    }

}
